Switch



y 1955 J. P. SMITH, JR 2,712,531

SWITCH Filed May 9, 1952 INVENTOR.

JOHN P. SMITHJR.

United Statesatent 2,712,581 Patented July 5, 1955 SWITCH John P. Smith, in, Verona, N. 3., assignor to The Daven Company, Newark, N. 1., a corporation of New Jersey Appiicntion May 9, 352, Serial No. 286,866

Claims. (Cl. 209-166) This invention relates to electrical switches and more particularly to switches for use in decade resistors, attenuators, or similar instruments where switch contacts sweep over stationary contacts.

The present invention comprehends an electrical switch wherein the movable contact members are yieldably carried by a movable carrying body of the switch for yielding movement relative thereto to provide a firm positive contact at all times with the stationary contacts with which they cooperate irrespective of wear or unevenness of the mounting of the stationary contacts.

An object of the present invention is to provide an electrical switch of this type which is compact, neat in appearance, relatively inexpensive to manufacture and one wherein the movable contacts, all except their stationary contact engaging ends, together with the yieldable means for urging them into stationary contact engaging-position are wholly enclosed in the main or carrying body of the switch.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a switch of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

in the drawings:

Figure l is a plan View of the switch showing it associated with stationary contacts with which it cooperates.

Figure 2 is an enlarged plan view of the improved switch. I

Figure 3 is a section through the switch taken on the line 33 of Figure 2.

Figure 4 is a section through the switch taken on the line 4-4 of Figure 2.

Figure 5 is a perspective view of the switch.

Figure 6 is a perspective view of one of the yieldable contact elements of the switch.

The switch of the present invention is applicable for use in various types of electrical instruments wherein movable contacts move over a series of stationary contacts, and is particularly useful in such instruments as attenuators, decade resistors and the like wherein an electrical circuit is closed between an inner ring contact and any one of a plurality of spaced stationary contacts.

Similar switches are shown in prior Patents 2,430,215 and 2,424,745.

Referring more particularly to the drawings, 1 indicates generically an instrument having an inner stationary ring contact 2 surrounded by a plurality of spaced stationary contacts 3, and in such an instrument the electrical circuit is closed between the inner ring contact in any one of the spaced contacts 3 by means of the switch of the present invention.

The switch proper is preferably molded of a suitable thermosetting plastic, although it may be made of any suitable material without departing from the spirit of the present invention. The switch includes a main carrying body 10 which has an opening 11 extending therethrough in which is seated a metal bearing sleeve or collar 12. The sleeve or collar 12 is provided with a threaded opening 13 to receive a set screw for attaching the switch to an operating shaft as is indicated at 5 in Figure 1 of the drawings so that the switch may be rotated about the axis of the opening 11 for positioning the switch in any desired position relative to the contacts 2 and 3.

The portion of the body 10 outwardly from the opening 11 is of greater thickness than the remaining portion of the body as shown at 14. The thickened portion 14 of the body has a recess 15 formed therein opening out through its upper side and a pair of spaced openings 16 extend inwardly through the body and opening into the recess 15.

These openings 16 are positioned one at each end of the recess as clearly shown in Figure 3 of the drawings and open out through the bottom or undersurface of the body 10.

Inverted U-shaped metallic contact members 17 and 18 are inserted in the recess 15 with their legs 19 extending outwardly through the openings 16. As clearly shown in Figure 3 of the drawings the inverted U-shaped member 17 is larger than the inverted U-shaped contact member 18 and the latter is nested within the former and the legs 19 of the inverted U-shaped contact 18 are shorter and project out of the body lti for a shorter distance than do the legs 19 of the inverted U-shaped contact 17. The connecting bar 20 of the inverted U-shaped contact 17 has depressions 21 formed therein inwardly of its ends and these depressions receive the inner ends of coil springs 22 which extend across the recess 15 and have their upper outer ends seated in recesses 23 formed in the cover 24. The connecting bar 20 of the inverted U-shaped contact 17 also has an opening 25 extending centrally therethrough through which the inner end of a coil spring 26 projects. The innermost end of the coil spring 26 en gages in a depression 27 in the connecting bar 28 of the inverted U-shaped contact 18. The outer end of the spring 26 engages in a recess 29 formed in the connecting bar of the inverted U-shaped contact 18, thus the two inverted U-shaped contacts 17 and 13 are yieldably urged downwardly so that the projecting ends of their legs 19 will be urged outwardly for engagement with either the contact ring 2 or one of the stationary contacts 3 and each of these inverted U-shaped contacts 17 and 18 will be permitted movement into or out of the recess 15 independently of the other thus permitting firm current-conducting contact engagement between the ends of the legs of the inverted U-shaped contacts with the stationary contacts irrespective of wear of the latter or irregularity in their mounting. The cover 24 is of the same shape as the enlarged portion 14 of the body 1 and it fits tightly and snugly against the upper face of the enlargement. Proper positioning of the cover 24 on the enlargement 14 is provided by means of positioning studs 36 formed on the enlargement 14 which are seated in recesses 31 formed in the cover 24. The cover 24 and the body 10 are provided with aligning openings 32, the ends of which are counterbored, to receive rivets 33 for firmly attaching the cover 24 to the body 10. Thus all of the inverted U- shaped contacts 17 and 18 except their projecting stationary contact engaging ends and the springs 22 and 26 are wholly closed within the main body of the switch and none of these relatively delicate parts are exposed for accidental displacement or disfigurement during use.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. In an electrical switch, a movable contact carrying body having a recess therein opening out through the upper surface of the body and provided with a pair of spaced openings opening from the inner end of said recess springs within said recess and engaging the connecting bars of said inverted U-shaped members, a cover attached to said body and closing said recess for wholly enclosing said springs and all of said U-shaped members except the outwardly projecting ends thereof, the connecting bar of the inverted U-shaped member in which the other inverted U-shaped member is nested having an opening therein throu h which one of said coil s rinszs nroiects c 7 r c: r

for engagement with the connecting bar of the inner U- shaped member whereby said inverted U-shaped members may move one independently of the other.

2. In an electrical switch, a movable contact carrying body having a recess therein opening out through the upper surface of the body and provided with a pair ot spaced openings opening from the inner end of said recess out through the underside of said body and having their outer sides aligning with the end walls of said recess, a pair of inverted U-shaped contacts nested one within the other and having their connecting bars in said recess and their legs projecting outwardly through said openings, springs within said recess and engaging the connecting bars of said inverted U-shaped members, a cover attached to said body and closing said recess for wholly enclosing said springs and all of said U-shaped members except the outwardly projecting ends thereof, said cover and connecting bars of said inverted U-shaped members having depressions therein receiving the ends of the coil I springs to prevent displacement of the springs.

3. In an electrical switch, a movable contact carrying body having a recess therein opening out through the upper surface of the body and provided with a pair of spaced openings opening from the inner end of said recess out through the underside of said body and having their outer sides aligning with the end walls of said recess, a pair of inverted U-shaped contacts nested one within the other and having their connecting bars in said recess and their legs projecting outwardly through said openings, springs within said recess and engaging the connecting bars of said inverted U-shaped members, a cover attached to said body and closing said recess for wholly enclosing sai springs and all of said U-shaped members except the outwardly projecting ends thereof, the connectingbar of the inverted U-shaped member in which the other inverted U-shaped member is nested having an opening therein through which one of said coil springs projects for engagement with the connecting bar of the inner U-shaped member whereby said inverted U-shaped members may move one independently of the other, the legs of one of said inverted U-shaped members being longer than the legs of the other inverted U-shaped member.

4. In an electrical switch, a movable contact carrying body having a recess therein opening out through the upper surface of the body and provided with a pair of spaced openings opening from the inner end of said recess out through the underside of said body and having their outer sides aligning with the end walls of said recess, a pair of inverted U-shaped' contacts nested one within the other and having their connecting bars in said recess and their legs projecting outwardly through said openings, springs within said recess and engaging the connecting bars of said inverted U-shaped rnembers,-and a cover attached to said body and closing said recess for wholly enclosing said springs and all of said U-shaped members except the outwardly projecting ends thereof.

5. An electrical switch as claimed in claim 4 wherein the outer sidesof the legs of the receiving one of the inverted U-shaped members engages the end walls of said'recess to provide steady, guided movement of the inverted U-shaped member. 7

References Cited in the file of this patent UNlTED STATES PATENTS 

